Depressed park wiper mechanism

ABSTRACT

In a preferred form, this disclosure relates to an actuating mechanism for oscillating a pair of windshield wipers across the windshield between inboard and outboard positions during running operation and for moving the wipers to a depressed park position when running operation is being terminated. The actuating mechanism comprises a housing means, an annular drive member rotatably supported by the housing means, a drive shaft rotatably supported by the housing means for rotation about its axis and drivingly connected with the annular drive member and a drive means operatively connected with the drive shaft for rotating the same. The actuating mechanism further comprises a crank assembly including a crank arm which is adapted to be connected with the wipers and a crank shaft which is supported by the annular drive member at an eccentric location for both rotational and axial movement relative thereto. The actuating mechanism further includes a stationary annular cam track carried by the housing means and an eccentric cam follower means carried by the crank shaft and a means operatively connected with the cam follower means for shifting the same between a first position in which it cooperably engages the annular drive member to cause the crank shaft to be rotated in unison with the annular drive member and through an orbit of a given radius during running operation of the wipers and a second position in which said eccentric cam follower is disengaged from the annular drive member and received within the stationary cam track to cause the annular drive member to rotate relative to the crank arm to increase the throw of the crank arm to cause the wipers to be moved toward their depressed park position when wiper operation is being terminated.

United States Patent 1 Carpenter 1 3,717,048 @451 Feb. 20, 1973 [54]DEPRESSED PARK WIPER MECHANISM [7 5] lnventor: Keith H. Carpenter,Kettering, Ohio [58] Field of Search "IS/250.16, 250.17; 74/600, 74/74,75, 42

[56] References Cited UNITED STATES PATENTS 3,091,128 5/1963 De Rees eta1 ..74/600 X 3,115,599 12/1963 Ziegler ....74/600 X 3,197,796 8/1965Kato et al ..l5/250.l7 3,242,520 3/1966 Carroll et al..... ....74/600 X3,665,772 5/1972 Beard et al. ..74/75 Primary ExaminerPeter FeldmanAttorney-W. E. Finken et al.

[5 7] ABSTRACT In a preferred form, this disclosure relates to anactuating mechanism for oscillating a pair of windshield wipers acrossthe windshield between inboard and outboard positions during runningoperation and for moving the 'wipers to a depressed park position whenrunning operation is being terminated. The actuating mechanism comprisesa housing means, an annular drive member rotatably supported by thehousing means, a drive shaft rotatably supported by the housing meansfor rotation about its axis and drivingly connected with the annulardrive member and a drive means operatively connected with the driveshaft for rotating the same. The actuating mechanism further comprises acrank assembly including a crank arm which is adapted to be connectedwith the wipers and a crank shaft which is supported by the annulardrive member at'an eccentric location for both rotational and axialmovement relative thereto. The actuating mechanism further includes astationary annular cam track carried by the housing means and aneccentric cam follower means carried by the crank shaft and a meansoperatively connected with the camfollower means for shifting the samebetween a first position in which it cooperably engages the annulardrive member to cause the crank shaft to be rotated in unison with theannular drive member and through an orbit of a given radius duringrunning operation of the wipers and a second position in which saideccentric cam follower is disengaged from the annular drive member andreceived within the stationary cam track to cause the annular drivemember to rotate relative to the crank arm to increase the throw of thecrank arm to cause the wipers to be moved toward their depressed parkposition when wiper operation is being terminated.

PATENTEDFEBZOISIS 717 04 SHEET 2 OF -2 MANIFOLD INVENTOR.

l I ATMOSPH EE DEPRESSED PARK WIPER MECHANISM The present inventionbroadly relates to a windshield wiping system, and in particular to anactuating mechanism for oscillating a pair of windshield wipers across awindshield of an automotive vehicle between inboard and outboardpositions during running operation and for moving the wipers to adepressed park position spaced from the inboard position when wiperoperation is being terminated.

An object of the present invention is to provide a new and improvedactuating mechanism for oscillating a windshield wiper across the outersurface of a windshield between inboard and outboard positions duringrunning operation and for moving the wipers to a depressed park positionspaced from the inboard position when wiper operation is beingterminated, and in which the actuating mechanism is of a relativelysimple and economical construction.

Another object of the present invention is to provide a new and improvedactuating mechanism for oscillating the windshield wiper across thewindshield between inboard and outboard positions during runningoperation and for moving the wiper to a depressed park position spacedfrom the inboard position when wiper operation is being terminated, andin which the mechanism includes a housing means, an annular drive memberrotatably supported by the housing means, a drive shaft supported by thehousing means for rotation about its axis and drivingly connected to thedrive member, a crank assembly including a crank arm which is adapted tobe connected with the wipers and a crank shaft which is supported by theannular drive member at an eccentric location for both rotational andaxial movement relative thereto, an annular stationary cam trackconcentric with the annular drive, member, an eccentric cam followermeans carried by the crank shaft and a means for shifting the crankassembly between a first position in which the eccentric cam followermeans drivingly engages the annular drive member to cause the crank armto be rotated in unison with the annular drive member through an orbitof a given radius during running operation of the wipers and a secondposition in which the eccentric cam follower is disengaged from theannular drive member and received within the annular cam track to causethe annular drive member to be rotated relative to the crank arm andeffect an increase in the throw of the crank arm to cause the wipers tobe moved to their park position when wiper operation is beingterminated.

The present invention further resides in various novel construction andarrangement of parts, and further objects novel characteristics andadvantages of the present invention will be apparent to those skilled inthe art to which it relates and from the following detailed descriptionof the illustrated embodiment thereof made with reference to theaccompanying drawings forming a part of this specification and in whichsimilar reference numerals or characters are employed to designatecorresponding parts throughout the FIG. 3 is a view like that shown inFIG. 2, but showing different parts thereof in different positions;

FIG. 4 is a view like that shown in FIG. 2, but showing'different partsthereof in different positions;

FIG. 5 is a fragmentary sectional view taken approximately along line 55of FIG. 2;

FIG. 6 is a fragmentary sectional view taken approximately along line 66of FIG. 2; and

FIG. 7 is a schematic view of a control circuit means for controllingoperation of the actuating mechanism of the present invention.

The present invention provides a novel-actuating mechanism for use in awindshield wiping system for oscillating a pair of windshield wipersacross the outer surface of the windshield between inboard and outboardpositions during running operation and to a depressed park positionspaced from the inboard posi? tion when wiper operation is beingterminated.

As representing a preferred embodiment of the present invention, FIG. 1of the drawings schematically shows the windshield wiping system A forwiping a windshield 10 of an automotive vehicle (not shown). Thewindshield wiping system A comprises a pair of suitable or conventionalwindshield wipers which are drivingly connected to drive pivot 16. Thedrive pivots are adapted to be rotatably supported by the body structureof the vehicle (not shown) at spaced locations adjacent the lower edgeof the windshield 10.

The wipers 15 are adapted to be oscillated in tandem across the outersurface of the windshield 10 between inboard and outboard positions,designated by the letters I and 0 in-FIG. 1 of the drawings, duringrunning operation and are adapted to be moved from their inboardposition I to a depressed park position P adjacent the lower edge of thewindshield 10 when running operation is being terminated. 1

The wipers 15 are actuated or oscillated between their inboard andoutboard positions and to their park position P by a novel actuatingmechanism 20 via a transmission linkage means 21. The novel actuatingmechanism 20 includes a rotatable crank assembly 23 having a crank arm24 which is rotated in the direction of the arrow 27. The transmissionlinkage 21 comprises a pair of crank arms 28 and 29 having one end fixedto one of the drive pivots 16 and the other end swivelly connected to across link 30. The transmission linkage also includes a drive link 32which is swivelly connected to the crank arm 28 at one end and with theother end being swivelly connected to a ball 33 carried by one end ofthe crank arm 24 (see FIG. 2). Rotation of the crank arm 24 in thedirection of the arrow 27 causes the transmission linkage 21 to bereciprocated to cause the wipers 15 to be oscillated in tandem acrossthe outer surface of the windshield 10.

The crank arm 24 has an effective radius r, during running operationwhich causes the wipers 15 to be oscillated between their inboard andoutboard positions I and 0. When wiper operation is being terminated andthe wipers 15 reach their inboard position the thrown or radius of thecrank arm is increased to r, to cause the wipers to be moved to theirdepressed park position P.

The novel actuating mechanism 20 comprises a metal casting or housing 40having an opening 41 therein. The opening 41 has first, second and thirddiameter portions 41a4lc which progressively decrease in diameterpreceding from their lower end toward the upper of the housing 40, asviewed in FIG. 2.

The housing means 40 supports the drive assembly 42. The drive assemblycomprises a unidirectional DC. motor 43 whose output or armature shaft44 is fixed to a worm 45. The worm 45 is in meshed engagement with theworm gear 46 fixed to a drive shaft 48. As shown in FIG. 2, the driveshaft 48 is rotatably supported adjacent its lower end via a bearing 50carried by an end cap or cover 52 suitably secured to the housing 40 atits lower end. The drive shaft 48 is also drivingly connected at itsupper end to annular drive member or bearing cap 53 rotatably supportedby the housing at its upper end. The drive shaft 48 includes anon-circular portion 48a which is received in the complementary shapedopening 54in the drive member 53 to provide a driving connectiontherebetween. The drive shaft 48 is also axially shiftable within theopening portion 54 of the annular drive member 53 and relative to thecover 52. The axial extent of the worm gear 46 is such that the wormgear 46 can be shifted with the drive shaft 48 while maintaining itsmeshed engagement with the worm 45.

The annular drive member 53 is held against relative axial movement by aflange 55 on the housing 40 at its upper end and by an annular rib 56 ona stationary cam track 58 carried by the housing 40 at the diameterportion 41b. The drive shaft 48 and the annular drive member 53 areconcentric and when the electric motor 43 is energized the drive shaft48 and the annular drive member 53 are rotated within the housing aboutthe longitudinal axis of the drive shaft 48 and annular drive member 53.

The crank assembly 23 is rotatably and eccentrically supported by theannular drive member 53. The crank assembly 23 is also supported formovement axially of the drive member 53. The crank assembly 23 comprisesthe crank arm 24 which has one end thereof secured to a crank shaft 60,the crank shaft being rotatably and slidably received within aneccentric opening 61 in the drive member 53. The longitudinal axis ofthe crank shaft 60 is spaced from, but extends parallel to thelongitudinal axis of the drive shaft 48 and the annular drive member 53.The crank assembly further includes an annular cam follower or canfollower means 70 eccentrically carried by the crank shaft 60. The camfollower 70 has its axis parallel to but spaced from the axis of thecrank shaft 60 and has an annular peripheral groove 71 therein. Thedrive shaft 48 has suitably secured thereto a collar 72 having aperipherally extending flange 73 which is received within the groove 71in the cam follower 70.

The crank assembly 23 is shiftable axially of the annular drive member53 between first and second positions. When in its first position, asshown in FIG. 2, the cam'follower 70 is received within thecomplementary shaped recess or opening 75 in the annular drive member todrivingly connect the crank assembly to the annular drive member 53.When the crank assembly 23 is drivingly connected to the annular drivemember 53, it is rotated in unison with the annular drive member aboutthe axis of the annular drive member 53 and with the crank arm 24 beingrotated through an orbit having an effective radius r,. When the crankarm has an effective radius r, the wipers are oscillated between theirinboard and outboard positions I and 0.

When the cam follower is shifted from its first position as shown inFIG. 2, towards its second posi- 5 tion, as shown in FIG. 3, it isdisengaged from the annular drive member 53 and is received by theannular cam track 58. The cam track 58 is formed in an annular plasticmember carried by the housing 40 and the cam track is eccentric withrespect to the axis of the 10 drive shaft 48 and the annular drivemember 53. The

cam track 58 is defined by annular side walls 81 and 82 and a radiallyextending top wall or flange 83 concentric with the axis or rotation ofthe drive member 53. The flange 83 is cut out orcut away to define a gapor recess 86 along a portion of its annular extent. The cam follower 70can enter the cam track 58 only when it is aligned with the cut outportion 86, which alignment occurs when the wipers are in their inboardposition I and the crank assembly 23 is in the position shown in FIG. 3.Thus, when the cam follower 70 is shifted from its first position towardits second position, as shown in FIG. 3, upon termination of wiperoperation, the cam follower 70 will engage the annular flange 83 untilit is aligned with the cut out portion 86 at which time the wipers willbe in their inboard position I.

When the cam follower 70 moves through the cut out portion 86 and is inthe cam track 58, continued rotation of the annular drive member 53 willcause the same to be rotated relative to the crank assembly 23. This isbecause the eccentric cam follower 70 must follow the contour of the camtrack 58. As the annular drive member 53 rotates, the crank assembly 23rotates about the axis of the crank shaft 60 in the opposite direction,since the eccentric cam follower 70 must follow the contour of theeccentric cam track 58; During this relative movement the crank arm 24remains, in effect, in the same disposition it had when the wipers l5.reached their inboard position I except that the crank arm 24 isradially shifted from its position shown in FIG. 3 toward its positionshown in FIG. 4 to increase the throw of the crank arm to r,.'When theannular drive member 53 has been rotated 180 subsequent to the camfollower 70 being received within the cam track 58 when the wipers arein their inboard position, the eccentric cam follower 70 will trip apark switch 85 carried by the cam track to de-energize the wiper motor43, and in a manner to be hereinafter more fully described.

When wiper operation is initiated and the wipers 15 are in their parkposition, the relative position of the parts are as shown in FIG. 4.When wiper operation is initiated the annular drive member 53 is rotatedin the direction of the arrow 27. During the first of rotation of theannular drive member53, the cam follower 70 follows the contour of thecam track 58 until it is aligned with the cut out portion 86 whereuponit is adapted to be shifted from its second position toward its firstposition, as shown in FIG. 2. During this relative movement theeffective radius of the crank arm is reduced from radius r, to radius r,which causes the wipers 15 to be moved from their park position P towardtheir inboard position I. The crank assembly is preventedfrom beingmoved toward its first position, as shown in FIG. 2, during thisrelative movement due to the engagement between the cam follower 70 andthe flange portion 83 of the cam track 58.

The crank assembly 23 is adapted to be shifted between its first andsecond positions by a shiftable means 90. The shiftable means 90comprises the worm gear 46 which serves as a piston and divides theopening portion 41a into upper and lower chambers 92 and 93. The wormgear 46 carries an annular seal 94 at its lower end which peripherallyengages the opening portion 41a of the housing 40.

The shiftable means 90 is normally biased toward the position shown inFIG. 2, which is also the position of the parts during running operationof the wipers 15. The shiftable means 90 is biased to the position shownin FIG. 2 by a compression spring 95 having one end in abuttingengagement with the lower side of the worm gear 46 and its other end inabutting engagement with the cover 52. The worm gear 46 can slidevertically relative to the worm 44 while maintaining its meshedengagement and when the worm gear 46 is in the position shown in FIG. 2,the collar 72 secured to the shaft 42 holds the eccentric cam follower70 within the opening 75 of the annular drive member 53.

The shiftable means 90 is adapted to be moved downwardly from itsposition shown in FIG. 2 towards its position shown in FIG. 3 when wiperoperation is being terminated. This downward movement of the shiftablemeans is effected by communicating the chamber 93 with a vacuum source,such as the inlet mainfold of the vehicle, via a conduit 96. The upperchamber 92 is vented at all times to the atmosphere via port 98. Whenvacuum pressure is applied to the chamber 93, the worm gear 46 is causedto be moved downwardly in opposition to the biasing force of thecompression spring 95. As the worm gear 46 is caused to be moveddownwardly the shaft 48 and collar 72 secured thereto is caused to bemoved downwardly. Downward movement of the collar 72 causes the camfollower 70 to be moved downwardly from its position shown in FIG. 2,toward its position shown in FIG. 3.

Operation of the windshield cleaning system A will be described withreference to the schematic control circuit means or diagram shown inFIG. 7. Control circuit means includes a D.C. battery 100 having oneterminal connected via a wire conductor to ground 6,, the park switch 85for the wiper motor 43, the electric wiper motor 43 which includes anarmature 101 and series and shunt field windings 102 and 103,respectively, an ignition switch 104, a resistor 105, a manuallyoperated wiper switch 107 having stationary terminals 108 and 110 and amovable bridging member 112, a park switch relay 113 and a valve means114 for selectively communicating the chamber 93 with either theatmosphere or the inlet manifold.

The wiper switch 107 could be of any suitable or conventionalconstruction. The movable bridging member 112 of the wiper switch 107 ismovable between an off position, a low speed position, and a high speedposition. The park switch 85 includes a stationary contact and a mobilecontact 85b carried by a leaf spring 850 which is self-biased toward aclosed position in which the contacts engage each other, but which isnormally held in an open position by the cam follower 70 when thewindshield wipers are in their park position P, as shown in FIG. 4.

When the operator of the vehicle desires low speed operation of thewindshield wiping system A, he will move the bridging member 112 of thewiper switch 107 from its off position to its low speed position, asshown by the dotted lines in FIG. 7. Movement of the bridging member 112to its low speed position also causes the valve means 114 to be moved,since the valve actuator 115 is operatively connected with the bridgingmember 112, to its open position in which it communicates the atmospherewith the chamber 93 via conduit 96. With the chamber 93 in communicationwith the atmosphere the spring 95 biases the shiftable means 90 towardsits first position, as shown in FIG. 2. However, since the cam follower70 is located beneath and in engagement with the flange 83 of the camtrack 58, the shiftable means will remain in the position shown in FIG.4 until the cam follower 70 is located within the cut out 86.

When the bridging member 112 is in the low speed position an electriccircuit is completed for energizing the park switch relay 113. Thiscircuit is from battery 100, wire 117, now closed ignition switch 104,wire 118, circuit breaker 120, wire 121, relay coil 113a of the relay113, wire 122, stationary contact 108, bridging member 112, wire 123, toground G Energization of the park switch relay 113 causes the core 113bthereof to move the leaf spring 850 and its associated contact 85b intoengagement with the stationary terminal 85a to close the park switch 85.The closing of park switch 85 completes circuits for energizing theseries and shunt field winding 102 and 103 and armature 101 of the wipermotor 43. These circuits are from battery 100, wire 117, now closedignition switch 104, wire 118, circuit breaker 120, wire 121, parkswitch 85, wire 125, series field winding 102, wire 134, armature 101,wire 136, to ground G and from wire 125, shunt field windings 103, wire135, stationary contact 110, bridging member 112, wire 123 to ground GIn the low speed position the shunt field windings 103 are fullyenergized. The completion of these circuits energizes the wiper motor 43for low speed operation.

When the wiper motor 43 is energized, it rotates the drive shaft 48 andthe annular drive member 53 in the direction of the arrow 27. During thefirst 180 of rotation of the annular drive member 53, it will rotaterelative to the crank assembly 23 and with the cam follower followingthe contour of the cam track 58. During this relative rotation, thethrow of the crank arm 24 is decreased from radius r, toward radius r,,which in turn causes the wipers 15 to be moved from their park positiontoward their inboard position. When the wipers 15 are in their inboardposition, which occurs when the annular drive member 53 is rotated 180,the cam follower 70 will be aligned with the cut out 86. When thisoccurs the spring 95 will move the worm gear 46, drive shaft 48 andcollar 72 in an upward direction toward the position shown in FIG. 2. Asthe collar 72 is moved in an upward direction it causes the cam follower70 to be moved from its second position, as shown in FIGS. 3 and 4,toward its first position, as shown in FIG. 2, in which it is receivedwithin the recess in the annular drive member. To aid in guiding the camfollower 70 into the recess 75, the cam follower is axially tapered onits upper side and the recess is axially tapered inwardly in acomplementary manner.

When the cam follower 70 is disposed within the recess 75, the crankassembly 23 is drivingly connected to the annular drive member 53 sothat further rotation of the latter causes the crank assembly 23 to berotated about the axis of the annular drive member 53, which in turncauses the wipers to be oscillated between their inboard and outboardpositions I and 0. Since the cam follower 70 is eccentric with respectto the axis of the crank shaft 60, the latter cannot be rotated when thecam follower 70 is received within the recess 75 and thus, the crankassembly 23 is drivingly connected to the annular drive member 53.

When the wiper switch bringing member 112 is moved from its low speedposition to its off position to terminate wiper operation, theaforedescribed circuit for the park switch relay 113 is broken, sincethe bringing member 112 disengages the stationary contact 110 in its offposition. The wiper motor 43, however, remains energized until thewipers 15 reach their park position, since the leaf spring 85c of thepark switch 85 is self-biased toward a closed position during runningoperation of the wipers 15 and since the cam follower 70 is not in thecam track 58 and thus disengaged therefrom, as shown in FIG. 2. The parkswitch 85 remains closed until the windshield wiper motor 43 moves thewipers 15 to their park position at which time the cam follower 70 willopen the park switch to de-energize the circuits for the wiper motor 43.Also, when the bridging member 112 is moved to its off position, thevalve member 114 is moved to its second position in which itcommunicates the inlet manifold with chamber 93 via conduit 94. Whenthis occurs, the shiftable means 90 is shifted from its position shownin FIG. 2 towards its position shown in FIG. 3.

If the windshield wipers 15 are not in their inboard position I when thebridging member 112 is moved to its off position and the valve member114 is moved to communicate the inlet manifold with the chamber 93, theshiftable means 90 is prevented from being moved towards its lowerposition, as shown in FIG. 3, due to the fact that the cam follower 70cannot be received within the cam track 58, since it will engage theupper side of the flange 83. Thus, the annular drive member and thecrank assembly 23 remain locked together until the cam follower 70 isaligned with the cut out 86 in the annular cam track 58. When the camfollower 70 is aligned with the cutout 86, the wipers 15 are in theirinboard position I and the vacuum pressure on the underside of the wormgear 46 will cause the shiftable means 90 to be moved downwardly tocause the cam follower 70 to be received within the cam track 58. Thisdisengages the drive connection between the annular drive member 53 andthe crank assembly 23 with the result that continued rotation of theannular drive member 53 through 180 of rotation causes the drive member53 to rotate relative to the crank assembly 23 and causes the crankassembly 23 to be shifted from its position shown in FIG. 3 towards itsposition shown in FIG. 4. and its effective radiusor throw to beincreased to radius r, to cause the wipers 15 to be moved from theirinboard position I to their park position P. When the wipers reach theirpark position P, the cam follower 70 will engage the park switch to openthe same and thus de-energize the wiper motor.

When the operator desires high speed operation, he will move thebridging member 112 of the wiper switch 107 to its high speed position,as indicated by the phantom lines in FIG. 7. Movement of the bridgingmember 112 to this position causes only the stationary contact 110 ofthe wiper switch 107 to be bridged. When in this position thehereinbefore described circuits for energizing the park switch relay 113and the series field windings 102 and armature 101 of the wiper motor 43are completed. The hereinbefore described circuit for energizing theshunt field windings 103 to ground G, is not completed, since thebridging member 112 does not bridge the contacts 108 and 110 in the highspeed position. When the bridging member 112 is in its high speedposition, the shunt field windings 103 are energized via a circuitthrough the resistor 105 to ground G, whereby the shunt field windingsare only partially energized which causes the wiper motor to operate athigh speed, and in a manner well known to those skilled in the art. Thelatter circuit is from battery 100, wire 117, now closed ignition switch104, wire 118, circuit breaker 120, wire 121, park switch 85, wire 125,shunt field windings 103, wire 135, resistor 105, wire 136 to ground 6,.

The manner in which the actuating mechanism 20 effects movement of thewipers to their park position P when wiper operation is being terminatedand from theirpark position P to their inboard position I when wiperoperation is being initiated is the same for high speed operation aspreviously described for low speed operation.

Although the illustrated embodiment thereof has been described in greatdetail, it should be apparent that certain modifications, changes, andadaptations may be made in the illustrated embodiment, and that it isintended to cover all such modifications, changes and adaptations whichcome-within the spirit of the present invention.

What is claimed is:

1. An. actuating mechanism for use in oscillating a windshield wiperacross the windshield between inboard and outboard positions duringrunning operation and for moving the wiper to a park position spacedfrom the inboard position when wiper operation is being terminatedcomprising: a housing means; an annular drive member rotatably supportedby said housing means; a drive shaft supported by said housing means forrotational and axial sliding movement relative thereto, said drive shaftbeing drivingly connected with said drive member and axially movablerelative thereto while maintaining said driving connection therebetween;a drive means operatively connected with said drive shaft for rotatingthe same and said drive member; a crank assembly including a crank armwhich is adapted to be operatively connected with the wiper and a crankshaft eccentrically and rotatably supported by said drive member; astationary cam track carried by said housing means and with the camtrack being eccentric with the axis of rotation of said drive member; aneccentric cam follower means carried by said crank shaft; and means forshifting said drive shaft and said cam follower means between a firstposition in which said cam follower means drivingly engages said annulardrive member to cause said crank assembly to be rotated with said drivemember about the axis of the latter during running operation and asecond position in which said ca'm follower means disengages saidannular member and is received in said cam track to cause said annularmember and said crank assembly to rotate relative to each other toincrease the throw of the crank arm to move the wipers from theirinboard position towards their park position when running operation isbeing terminated.

2. An actuating mechanism for use in oscillating a windshield wiperacross the windshield between inboard and outboard positions duringrunning operation and for moving the wiper to a park position spacedfrom the inboard position when wiper operation is being terminatedcomprising: a housing means; an annular drive member rotatably supportedby said housing means; a drive shaft supported by said housing means forrotational and axial sliding movement relative thereto, said drive shaftbeing drivingly connected with said drive member and axially movablerelative thereto while maintaining said driving connection; a drivemeans operatively connected with said drive shaft for rotating the sameand said drive member; a crank assembly including a crank arm which isadapted to operatively connect with the wiper and a crank shaft which issupported by said annular drive member at an eccentric location for bothrotational and axial movement relative thereto; a stationary cam trackcarried by said housing means and with the cam track being eccentricwith respect to the axis of rotation of said annular drive member; anannular cam follower means eccentrically supported by said crank shaft;said crank assembly being shiftable axially of said annular drive memberbetween a first position in which said eccentric cam follower isreceived in a complementary shaped opening in the annular drive memberto cause the crank assembly and annular drive member to be rotated inunison about the axis of the annular drive member during runningoperation of the wiper and a second position in which said eccentric camfollower is disengaged from the annular drive member and received withinthe cam track which causes said annular drive member to rotate relativeto the crank assembly to cause the crank arm to be radially shifted withrespect to the annular drive member to increase the thrown of the crankarm and move the wipers toward their park position when wiper operationis being terminated, means carried by said drive shaft cooperablyengageable with said eccentric cam follower for shifting the samebetween its positions in response to movement of the drive shaft andmeans operatively associated with the drive shaft for effecting shiftingmovement of the drive shaft and the cam follower means between itspositions.

3. An actuating mechanism for use in oscillating a windshield wiperacross the windshield between inboard and outboard positions duringrunning operation and for moving the wiper to a park position spacedfrom the inboard position when wiper operation is being terminatedcomprising: a housing means; an annular drive member rotatably supportedby said housing means; a driveshaft supported by said housing means forrotational and axial sliding movement relative thereto, said drive shaftbeing drivingly connected with said drive member and axially movablerelative thereto while maintaining said driving connection; a drivemeans including a worm gear fixed to said drive shaft for rotating thesame and said drive member; said crank assembly including a crank armwhich is adapted to operatively connect with the wiper and a crank shaftwhich is supported by said annular drive member at an eccentric locationfor both rotational and axial movement relative thereto; a stationarycam track carried by said housing means and with the cam track beingeccentric with respect to the axis of rotation of said annular drivemember; an annular cam follower means eccentrically supported by saidcrank shaft; said crank assembly being shiftable axially of said annulardrive member between a first position in which said eccentric camfollower is received in a complementary shaped openingin the annulardrive member to cause the crank assembly and annular drive member to berotated in unison about the axis of the annular drive member duringrunning operation of the wiper and a second position in which saideccentric cam follower is disengaged from the annular drive member andreceived within the cam track which causes said annular drive member torotate relative to the crank assembly to cause the crank arm to beradially shifted with respect to the annular drive member to increasethe throw of the crank arm and move the wipers toward their parkposition when wiper operation is being terminated, a collar carried bysaid drive shaft and cooperably engageable with said eccentric camfollower for shifting the same between its positions in response tomovement of the worm gear and drive shaft, spring means operativelyengaged with said worm gear for biasing said crank assembly toward itsfirst position, andmeans for communicating one side of said worm gearwith a vacuum source to effect movement of the crank assembly toward itssecond position when wiper operation is being terminated.

1. An actuating mechanism for use in oscillating a windshield wiperacross the windshield between inboard and outboard positions duringrunning operation and for moving the wiper to a park position spacedfrom the inboard position when wiper operation is being terminatedcomprising: a housing means; an annular drive member rotatably supportedby said housing means; a drive shaft supported by said housing means forrotational and axial sliding movement relative thereto, said drive shaftbeing drivingly connected with said drive member and axially movablerelative thereto while maintaining said driving connection therebetween;a drive means operatively connected with said drive shaft for rotatingthe same and said drive member; a crank assembly including a crank armwhich is adapted to be operatively connected with the wiper and a crankshaft eccentrically and rotatably supported by said drive member; astationary cam track carried by said housing means and with the camtrack being eccentric with the axis of rotation of said drive member; aneccentric cam follower means carried by said crank shaft; and means forshifting said drive shaft and said cam follower means between a firstposition in which said cam follower means drivingly engages said annulardrive member to cause said crank assembly to be rotated with said drivemember about the axis of the latter during running operation and asecond position in which said cam follower means disengages said annularmember and is received in said cam track to cause said annular memberand said crank assembly to rotate relative to each other to increase thethrow of the crank arm to move the wipers from their inboard positiontowards their park position when running operation is beingterminated.
 1. An actuating mechanism for use in oscillating awindshield wiper across the windshield between inboard and outboardpositions during running operation and for moving the wiper to a parkposition spaced from the inboard position when wiper operation is beingterminated comprising: a housing means; an annular drive memberrotatably supported by said housing means; a drive shaft supported bysaid housing means for rotational and axial sliding movement relativethereto, said drive shaft being drivingly connected with said drivemember and axially movable relative thereto while maintaining saiddriving connection therebetween; a drive means operatively connectedwith said drive shaft for rotating the same and said drive member; acrank assembly including a crank arm which is adapted to be operativelyconnected with the wiper and a crank shaft eccentrically and rotatablysupported by said drive member; a stationary cam track carried by saidhousing means and with the cam track being eccentric with the axis ofrotation of said drive member; an eccentric cam follower means carriedby said crank shaft; and means for shifting said drive shaft and saidcam follower means between a first position in which said cam followermeans drivingly engages said annular drive member to cause said crankassembly to be rotated with said drive member about the axis of thelatter during running operation and a second position in which said camfollower means disengages said annular member and is received in saidcam track to cause said annular member and said crank assembly to rotaterelative to each other to increase the throw of the crank arm to movethe wipers from their inboard position towards their park position whenrunning operation is being terminated.
 2. An actuating mechanism for usein oscillating a windshield wiper across the windshield between inboardand outboard positions during running operation and for moving the wiperto a park position spaced from the inboard position when wiper operationis being terminated comprising: a housing means; an annular drive memberrotatably supported by said housing means; a drive shaft supported bysaid housing means for rotational and axial sliding movement relativethereto, said drive shaft being drivingly connected with said drivemember and axially movable relative thereto while maintaining saiddriving connection; a drive means operatively connected with said driveshaft for rotating the same and said drive member; a crank assemblyincluding a crank arm which is adapted to operatively connect with thewiper and a crank shaft which is supported by said annular drive memberat an eccentric location for both rotational and axial movement relativethereto; a stationary cam track carried by said housing means and withthe cam track being eccentric with respect to the axis of rotation ofsaid annular drive member; an annular cam follower means eccentricallysupported by said crank shaft; said crank assembly being shiftableaxially of said annular drive member between a first position in whichsaid eccentric cam follower is received in a complementary shapedopening in the annular drive member to cause the crank assembly andannular drive member to be rotated in unison about the axis of theannular drive member during running operation of the wiper and a secondposition in which said eccentric cam follower is disengaged from theannular drive member and received within the cam track which causes saidannular drive member to rotate relative to the crank assembly to causethe crank arm to be radially shifted with respect to the annular drivemember to increase the thrown of the crank arm and move the wiperstoward their park position when wiper operation is being terminated,means carried by said drive shaft cooperably engageable with saideccentric caM follower for shifting the same between its positions inresponse to movement of the drive shaft and means operatively associatedwith the drive shaft for effecting shifting movement of the drive shaftand the cam follower means between its positions.